This invention relates to foamed alkenyl aromatic polymers.
The use of styrene polymers in the production of foamed articles is well recognized. Particularly well known is the use of such foamed polymers in building and construction industries for insulative and decorative purposes. Unfortunately, however, such polymers burn readily and continuously upon exposure to flame.
It has been a widespread practice to reduce the propensity of such polymers to ignite by incorporating into them various phosphorus, nitrogen and halogen containing additives. A disadvantage in using such additives has been the detrimental effect such additives have on the physical properties of the foamed styrene polymers. Also, upon exposure to flame, such polymers having reduced ignition propensity melt or drip. This melt often ignites as readily as polymer containing no additive. As a result, a puddle of burning polymer is formed that evolves great quantities of black smoke.
In view of the aforementioned deficiencies of conventional styrene polymer foams, it is highly desirable to provide a styrene polymer foam which has a reduced propensity to propagate combustion and does not melt upon exposure to flame.